If you're running on or anything past 2.2.1 MWM, you should be able to use the tune tool (the screwdriver up in the top) to tune the idle.
If it's TimEK9's RB26, this should show an idle and a redline slider.
Click the engine block.
Move the idle one a little higher and see if it makes any difference.
This account is pretty much dead, my wip is dead, gom (also dead) killed starquest and the hdd it was on died.
But BeamNG is getting a Jeep from me now, which is fun. IIIIIIIII
